Unveiling the role of in situ sulfidation and H2O excess on H2S decomposition to carbon-free H2 over cobalt/ceria catalystsUnveiling the role of in situ sulfidation and H2O excess on H2S decomposition to carbon-free H2 over cobalt/ceria catalysts Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2025-05-282023enThe emerging energy and environmental concerns nowadays are highlighting the need to turn to clean fuels, such as hydrogen. In this regard, hydrogen sulfide (H2S), an abundant chemical compound found in several natural sources and industrial streams, can be considered a potential carbon-free H2 source through its decomposition. In the present work, the H2S decomposition performance of Co3O4/CeO2 mixed oxide catalysts toward hydrogen production is investigated under excess H2O conditions (1 v/v% H2S, 90 v/v% H2O, Ar as diluent), simulating the concentrated H2S-H2O inflow by the Black Sea deep waters. The effect of key operational parameters such as feed composition, temperature (550–850 °C), and cobalt loading (0–100 wt.%) on the catalytic performance of Co3O4/CeO2 catalysts was systematically explored. In order to gain insight into potential structure-performance relationships, various characterization studies involving BET, XRD, SEM/EDX, and sulfur elemental analysis were performed over the fresh and spent samples. The experimental results showed that the 30 wt.% Co/CeO2 catalyst demonstrated the optimum catalytic performance over the entire temperature range with a H2 production rate of ca. 2.1 μmol H2∙g−1·s−1 at 850 °C and a stable behavior after 10 h on stream, ascribed mainly to the in-situ formation of highly active and stable cobalt sulfided phases.The work was performed within the frame of the joint program Black-Sea ERA.NET under the FP-7 initiative of the European Commission and funded by the Greek General Secretariat for Research and Technology GSRT (grant No. 11BS_10_28) and the project “Development of New Innovative Low Carbon Footprint Energy Technologies to Enhance Excellence in the Region of Western Macedonia” (MIS 5047197) which is implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014–2020) and co-financed by Greece and the European Union (European Regional Development Fund).http://creativecommons.org/licenses/by/4.0/Catalysts133Kraia_et_al_Catalysts_13(3)_2023.pdfChania [Greece]Library of TUC2025-05-28application/pdf3.7 MBfree Kraia Tzouliana Varvoutis Georgios Marnellos, Georges E Konsolakis Michail Κονσολακης Μιχαηλ MDPI H2S decomposition/reforming H2O excess conditions Carbon-free H2 production Co3O4/CeO2 catalysts Cobalt sulfide phase